At the end of your meditation session, you’ll have the option to send a “Thanks for meditating with me” message to other participants.
Here’s how:
After tapping Finish, scroll to the bottom of the screen.
You’ll see the users who meditated with you.
Tap on the profiles of the people you’d like to thank.
Click the “Thanks for meditating with me” button.
Note: The button will only appear if the recipient has this feature enabled in their settings.

To enable/disable the Thanks for Meditating feature, go here.